Stabilized polypropylene compositions



United States Patent U.S. Cl. 26045.75 23 Claims ABSTRACT OF THEDISCLOSURE This invention relates to a heat and light resistantpolypropylene composition comprising a polypropylene and, as thestabilizing mixture therefor,

about 0.01% to about 5.0% by weight of the polypropylene of (a), as anultraviolet absorber, a compound of the formula R Sn I X b wherein R isa radical selected from the group consisting of alkyl of 1-l2 carbonatoms, cycloalkyl, aryl, and benzyl, X is selected from the groupconsisting of residues of the formulae R and R" are each selected fromthe group consisting of alkyl of 1-12 carbon atoms, alkoxyl of1-12*carbon atoms, phenyl, and oxygen exhibiting a direct bond to saidSn atom, a and b are each an integer from 1 to 3, and c and a are eachan integer from 0 to 2;

about 0.01% to about 5.0% by weight of the polypropylene of (b), as ananti-discoloring agent, a compound of the formula wherein R is selectedfrom the group consisting of hydrogen, alkyl of 1-18 carbon atoms,phenyl, alkaryl, and benzyl;

about 0.01% to about 2.0% by weight of the polypropylene of (c), asantioxidant, a compound of the formula ami. ilzh -ig (53% h wherein Q Qand Q, are each selected from the group consisting of hydroxyl, alkyl,of 1-12 carbon atoms, alkoxyl of 1-12 carbon atoms, and radicals of theformulae -NHCOR, and -CHZOHZCOOR in which when not less than tworadicals of each of Q Q and Q attach to a benzene nucleus, they may bethe same or different and R, R, R and R are each alkyl of 118 carbonatoms, Z and Z are each selected from the group consisting of sulfur,oxygen, and alkylene of 1-4 carbon atoms, d, e, f, and g are each aninteger 1-3, and his an integer 0-1; and

about 0.01% to about 2.0% by weight of the polypropylene of (d), as aperoxide decomposer, a compound of the formula wherein R is alkylene of1-12 carbon atoms, and R' is alkyl of 1-18 carbon atoms.

This invention relates to polypropylene compositions having improvedcolor stability to the degradative effects of heat and light.

The exposure of polyolefine to heat and light usually causes itsdiscoloration, color fading of dyed fibers, lowering of the mechanicalstrength of molded articles,

cloudiness of films, etc. In order to overcome such de-.

wherein R is a radical selected from the group consisting of alkyl of1-12 carbon atoms, cycloalkyl, aryl, and benzyl, X is selected from thegroup consisting of residues of the formulae 0 o N t@ t o@ (J N (Ia/I)i)d R' and R" are each selected from the group consisting of alkyl of1-12 carbon atoms, alkoxyl of 1-12 carbon atoms, phenyl, hydroxyl, andhalogen in which the hydroxyl group may be attached to the organotinmoiety, a and b are each an integer from 1 to 3, and c and d are each aninteger from 0 to 2.

Polypropylene containing the UV. absorber, however, has unsatisfactorystability against the deleterious effect of heat as discoloring gray todark gray when treated at about 300 C. It may be considered to be due tothe reaction of commonly used antioxidants of sulfur or phenol type withthe above mentioned organotin ultraviolet absorber.

RaSn

The object of this invention is to reduce or eliminate such an adverseeffect and the invention relates to a heat.

and light resistant polypropylene composition which comprises apolypropylene and, as the stabilizing mixture therefor,

(a) As an ultraviolet absorber, a compound of the formula herein R is aradical selected from the group consisting f alkyl of 1-12 carbon atoms,cycloalkyl, aryl, and enzyl, X is selected from the group consisting ofresidues f the formulae ii -to and -N\ and R" are each selected from thegroup consisting of lkyl of 1-12 carbon atoms, alkoxy of 1-12 carbonatoms, henyl, hydroxyl, and halogen in which the hydroxyl roup may beattached to the organotin moiety, a and b re each an integer from 1 to3, and c and d are each an lteger from to 2;

(b) As an anti-discoloring agent, a compound of the )rmula 'herein R isselected from the group consisting of hydroen, alkyl of 1-18 carbonatoms, phenyl, alkaryl, and enzyl;

(c) As an antioxidant, a compound of the formula herein Q Q and Q areeach selected from the group onsisting of hydroxyl, alkyl of 1-12 carbonatoms, lkoxyl of 1-12 carbon atoms, and radicals of the formulae hereinR is alkylene of 1-12 carbon atoms, and R is lkyl of 1-18 carbon atoms.

Illustrative of the organophosphorus compounds within 1e scope of theforegoing formula (b) that are useful in re invention are the following:

Dl-lauryl hydrogen phosphlte C12H250)2P 0H Tributyl phosphlte (C4HoO)aPTris-(2-ethy1hexyl) phosphite (OaEi1O)aP Trldecyl phosphite 010E210 )3 PTris-(nonylphenyl) phosphite Triphenylphosphite (-o-) P Trlbenzylphosphite (@omo) P Dlphenyl decylphosphite (O-) P 0 0101121 Illustrativeof the organotin compounds within the scope of the foregoing formula (a)that are useful are the following:

5 (butyDzSn O (F 1 O (octy)2Sn 11 o (phenyDzSn O JL (benzy1) SnO 0 llOCaHn/Q but 1) Sn 0 N y 2 (octyl) Sn "0 N 2 (phen 1) Sn 0 N y 2 (benz 1)Sn-0 N OCH; 6O

(octy1)zSn\\ =0 (octyDzSn -O In these formulae, butyl signifies a butylradical, octyl is an octyl radical phenyl is a phenyl radical and benzylis a benzyl radical.

this invention is in the range of 001- .0 parts by weight 6 EXAMPLE 1Sample A was made' by mixing in a Henschel mixer the following:

per 100 parts by weight of polypropylene, preferably in Parts the rangeof (H40 part by Weight which will va-ry Pol ro lene havin intrinsicviscosit of 210 as depending upon the kind of molded articles and themode 5 g f on Solution at C.) 100 of their 2 6-di-t-but l-4-meth l hen Itrade name' Ionol 01 Illustrative of the useful phenolic compoundswithin the Dilauryl tgiodipropisggate scope of the foregoing formula (c)are the following: Dibutyltin bis (2 benZoy1 s octoxyphenoxide) O3 102,6 di t butyl 4 methylphenol Trls ethylheXyl) phosphlte 032,6-di-t-butyl-4-butylphenol For purposes of comparison, sample B wasmade by 2,6-di-tamyl-4-methylphenol mixing in a Henschel mixer thefollowing: 2,6-di-t-butyl-4-ethylphenol Parts 2,4-di-isooctylphenolPolypropylene 100 2-methoxy-6-ethylphenol Ionol 0.1 2,2-methylene-bis-(4methyl-6-t-butylphenol) Dilauryl thiodipropionate 0.44,4'-methylene-bis-(2,6-di-isopropylphenol) Dibutyltinbis-(Z-benzoyl-S-octoxyphenoxide) 0.34,4-thiobis-(2-t-butyl-6-methylphen01) For 00 arison sam le C was made.b mixin in a 2,2'-thiobis-(6-t-butylr4-methylphenol)Henschelnnlfxerthefonofling. y g NN-di-(n-dodecyl)-3 S-di-t-but l-4-h dh l- I p Y Y YP 3 Parts acetamlde Polypropylene 100 t-CJH Ionol 0.1Dilauryl thiodipropionate 0.4 OH OH2OON For comparison, sample D wasprepared from poly- L 0121125 propylene without the addition of anyadditives. i v h 01 Sheets 0.8 mm. thick were made by milling samplesearoy p'ammop en A,B, C and D on a mixing roll heated to 150i0.5 C. H0NH CO C H For heat stability test, grains 0.8 mm. formed from thesesheets were placed into test tubes of 5 mm. in inside diameter and 8 mm.in outside diameter, and the dis- 'dl't'buty1 4'hydmxypheny1 p mp lomcand Octyl coloration was observed one hour after the test tubes t 4Hv 35were put into oil heated to 270 C. The sheets were also tested in afade-o-meter (equipped with a xenon lamp, 01320320000811" free fromultraviolet rays below the wavelength of 300 111,41.) for lightresistance, being irradiated for 500 hours PC4119 and for 1,000 hours.

' TABLE I Color of grains Appearance of sheet Original Heated 270 Samplesheet C./1 hr. Lighted 500 hrs. Lighted 1,000 hrs.

A Pure white Pure White No changes No changes, white,

no cracks. B do Dark gray Slightly yellow, no Slightly yellow, no

other changes. cracks, not broken when fingered. C "do Gray A few cracksAlot; of cracks broken when fingered. D Light yellow Brown A lot ofcracks broken when fingered; dark yellow.

Illustrative of the useful sulfur containing compounds EXAMPLE 2W1th1n.th? scope of the foregoing formula (d) are the 0.4 part ofdilauryl thiodipropionate, 0.1 part of Ionol, followmg' o 0.3 part ofdibutyltin bis-(2-benZotriazolyl-4-methyl- Dilauryl-B-thiodipropionatephenoxide) and 0.3 part of tris-(Z-ethylhexyl)-phosphiteDistearyl-B-thiodipropionate were added to 100 parts of polypropylenewith 2.10 of intrinsic viscosit measured in Tetraline solution at 135The added amount of each of the antioxidant and the C and treated thesame Way as in Example 1 and the P decomposef 18 in i range of Parts bymixture hereinafter called sample B. 0.4 part of dilauryl Welght P 0 P sy Welght of p yp pylene. thiodipropionate, 0.1 part of Ionol and 0.3part of di- The molded article formed by the practice of this inbutyltin bis(2-benzotriazolyl-4-methylphenoxide) were vention exhibits afair white color, while the one obadded to such polypropylene andsimilarly treated and tained from the same polypropylene compositionwithout the mixture hereinafter called sample F. i the addition oforgan-opho sphorus compound is discolored Samples C and D were melted tobe spun for compariconsiderably. In order to obtain the compositions ofthis son with samples E and F. The fibers made from samples invention,each raw material is mixed in a Henschel mixe'r, C, E, and F were purewhite-colored, while the fiber from a llbbOI'l screw mixer, or a V-typemixer. sample D was light yellow-colored. Heat resistance was Unlessotherwise mdicated, parts of materials are ex- 7 examined on thesefibers in the same way as in Example pressed in terms of parts byweight.

1. Moreover, in order to examine the light resistance,

Discoloration after 1 hr. Original at 270 C.

E Pure white-- Pure white. No changes in more than 30 time washings.

F do Yellow Yellow in 30 35 time washings.

O do Dark white- Yellow in 20 18 time washings.

D Light yellow Brow-n Yellow in 1 time washings.

Tensile strength Light resistance Sample in washing time 10 EXAMPLE 30.4 part of dilauryl thiodipropionate, 0.1 part of Ionol, 0.3 part ofdioctyltin bis-(2-benzoyl-5-dodecyloxyphenoxide) and 0.3 part ofdiphenyldecylphosphite were addedv to 100 parts of polypropylene with2.10 of intrinsic viscosity measured in Tetraline solution at 135 C.,and the mixture treated in the same way as in Example 1 is hereinaftercalled sample G. Sample H was made in the same way as Example 1 exceptadding no diphenyldecylphosphite. Sample I was made in the same way asin sample G except replacing dioctyltinbis-(Z-benzoyl-S-dodecyloxyphenoxide) by 0.3 part of dioctyltinbis-(Z-benzotriazolyl-4-methylphenoxide). Samples C and D were also usedfor comparison. Each example was put into test tubes with 5 mm. insidediameter and 7 mm. outside diameter and treated at 270 C. for 6 0minutes in the atmosphere of nitrogen gas. After that, films with 1 mm.thick, 10 mm. wide and 40 mm. long were made to be examined on oxidationstability in Geer aging tester with heat wind circulation mechanism at140 C. The same films were put into a fade-o-meter with carbon arc lampas light source and examined on light stability at 40 C. The results areshown in Table 3. In the table, degradation time in a Geer aging testermeans the time till whitecolored powder come out on the surface of thefilms or cracks are brought about. The test results by a fade-ometer areshown by the time till the proportion of infrared absorption degree (E1710 cmf /E 9'70 cm.- of the films reaches to 0.1 after infra-redabsorption spectra of the exposed films are measured.

TAB LE III Results in fadeometer (hour) Over 1,000 Over 1,000 Over 1,200

Discoloration after 1 hr. at Sample 270 0. Film G Pure white White Lightyellow. ight yel1ow Pure white White Dark white Dark white 700 Lightyell0w Yellow What is claimed is: 1. A stabilizing compositioncomprising: (A) an organotin compound of the general formula:

and N 8 wherein R and R" are each selected from the group consisting ofalkyl of 1-12 carbon atoms, alkoxy of l-12 carbon atoms, phenyl, andoxygen exhibiting a direct bond to said Sn atom, a and b are each aninteger from 1 to 3, and-c and d are each an integer from 0 to 2;

(B) a compound of the formula:

wherein R is selected from the group consisting of hydrogen, alkyl of1-18 carbon atoms, phenyl, alkaryl, and benzyl;

(C) a compound of the formula:

I tti (Q0. (a. g (A... 1

wherein Q Q and Q are each selected from the group consisting of alkylof 1-12 carbon atoms, alkoxy of 112 carbon atoms, radicals of theformulae:

in which when not less than two radicals of each of Q Q and Q attach toa benzene nucleus, they may be the same or diiferent and R, R", R and Rare each alkyl of 1-18 carbon atoms, and hydroxyl such that not morethan two of Q Q and Q, are hydroxyl when h is 1, Z and Z are eachselected from the group consisting of sulfur, oxygen, and alkylene of1-4 carbon atoms, d, e, f, and g are each an integer 1-3, and h is aninteger 0-1; and

(D) a compound of the formula:

S(RCOOR') wherein R is alkylene of 1-12. carbon atoms, and R' is alkylof 1-18 carbon atoms.

2. A stabilizing composition as claimed in claim 1 wherein R is an alkylgroup of 1-12 carbon atoms.

3. A composition as claimed in claim 1 wherein the organotin compound(A) is l (butyl) zSn 0 4. A composition as claimed in claim 1 whereinthe organotin compound (A) is t (octyDzSn O 0 aHn 2 5. A composition asclaimed in claim 1 wherein the organotin compound (A) is (phenyl) zSn 96. A composition as claimed in claim 1 wherein the organotin compound(A) is ban 1 S W )a 11 0 0 sHn 7. A composition as claimed in claim 1wherein the organotin compound (A) is (buty1)2Sn 8. A composition asclaimed in claim 1 wherein the organotin compound (A) is organotincompound (A) is (phenyDzSn F-O N i2 10. A composition as claimed inclaim 1 wherein the organotin compound (A) is (benzyDzSn-O N 11. Acomposition as claimed in claim 1 wherein the organotin compound (A) isOCHZ 12. A composition as claimed in claim 1 wherein the organotincompound (A) is i (octyDSm I 13. A stabilized polypropylene-containingcomposition comprising:

(A) an organotin compound of the general formula:

RES

wherein R is a radical selected from the group consisting of alkyl of1-12 carbon atoms, aryl, and benzyl, X is selected from the groupconsisting of residues of the formulae:

(Rm N (Rod wherein R and R" are each selected from the group consistingof alkyl of 1-12 carbon atoms, alkoxy of 1-12 7 carbon atoms, phenyl,and oxygen exhibiting a direct bond iQFiQh wherein Q Q and Q are eachselected from the group consisting of alkyl of 1-12 carbon atoms, alkoxyof 112 carbon atoms, radicals of the formulae:

, -NHCOR, and CH2OH:COOR

in which when not less than two radicals of each of Q Q and Q attach toa benzene nucleus, they may be the same or different and R, R", R and Rare each alkyl of 1-18 carbon atoms, and hydroxyl such that not morethan two of Q Q and Q are hydroxyl when h is 1, Z and Z are eachselected from the group consisting of sulfur, oxygen, and alkylene of 14carbon atoms, d, e, f, and g are each an integer 1-3, and h is aninteger 0-1; and

(D) a compound of the formula:

wherein R is alkylene of 1-12 carbon atoms, and R is alkyl of 1-18carbon atoms.

14. A stabilizing polypropylene-containing composition as claimed inclaim 13 wherein the organotin compound 15. A stabilizingpolypropylene-containing composition as claimed in claim 13 wherein theorganotin compound (A) is 0 ali" 16. A stabilizingpolypropylene-containing composition as claimed in claim 13 wherein theorganotin compound (A) is (phenyDzSn 17. A stabilizingpolypropylene-containing composition as claimed in claim 13 wherein theorganotin compound (A) is (benzyl);Sn-O

OCsHn 18. A stabilizing polypropylene-containing composition as claimedin claim 13 wherein the organotin compound (A) is 19. A stabilizingpolypropylene-containing composition as claimed in claim 13 wherein theorganotin compound (A) is (Octyh Sn 0 20. A stabilizingpolypropylene-containing composition as claimed in claim 13 wherein theorganotin compound (Phenyl): Sn 0 1661 6511 sn o 2 1. Astabilizingpolypropylene-containing composition as claimed in claim 13 wherein the,organotin compound (A) is 22. A stabilizing polypropylene-containingcomposition as claimed in claim 13 wherein the organotin compound 23. Astabilizing polypropylene-containing composition as claimed in claim 13wherein the .organotin compound (A) is 6mm s55 OG12H25 2 ReferencesCited I UNITED STATES PATENTS Mener et a1 26045.85 Peterson et a1.26045.85

Hicker et a1 26023 DONALD E. czAJA, Primary Examiner U. P. HOKE,Assistant Examiner 6 us. 01. X.R.

Hechenbleikner 260-4575

